A semiconductor device includes a substrate including a logic cell region and a connection region, a dummy transistor on the connection region, an intermediate connection layer on the dummy transistor, a first metal layer on the intermediate connection layer, an etch stop layer between the intermediate connection layer and the first metal layer, a through contact below the first metal layer penetrating the connection region, an upper portion of the through contact protruding above the etch stop layer, and a protection insulating pattern on the etch stop layer covering the upper portion of the through contact. The protection insulating pattern covers an upper side surface of the through contact and a top surface of the through contact.